Let #b > a > 0# be constants. Find the area of the surface generated by revolving the circle #(x − b)^2 + y^2 = a^2# about the y-axis?

Let #b > a > 0# be constants. Find the area of the surface generated by revolving the circle #(x − b)^2 + y^2 = a^2# about the y-axis?